Earlier, we proposed an inexpensive method to improve the performance of the conventional dual-head SPECT systems for I-123 dopamine transporter (DAT) imaging of Parkinson Disease. In this approach, the collimator on one head is replaced with a multi-pinhole (MPH) collimator while retaining the conventional collimator on the other head, thus enabling combined MPH/Parallelbeam (or Fanbeam) acquisition. The original MPH design consisted of 9 apertures with rectangular entrance/exit ports covering a cylindrical volume of interest (VOI) around the striatum with minimal multiplexing. Our main goal in this work is to increase the sensitivity of this system by adding more pinholes and allowing multiplexing. For a more efficient usage of the available detector coverage, we also proposed the usage of pinholes with circular apertures and elliptical ports referred to as 'lofthole' herein. Circular apertures are desired because of the uniform spatial resolution, more accurate point spread function modeling and fabrication while the elliptical ports provide more flexibility in the detector coverage compared to circular ports. In this preliminary work, we present a comparison of 9, 13, 17 and 16 pinhole configurations for conic-holes (circle bases) and loftholes (circular and elliptic bases) through projections obtained from GATE Monte Carlo software.